GB/T 4103.10-2000 Chemical analysis methods for lead and lead alloys - Determination of silver content
Some standard content:
GB/T4103.10---2000
This standard is a revision of the determination method of silver content in GB/T4103.12--1983 "Chemical analysis method of lead-based alloys - Atomic absorption spectrophotometric determination of silver, zinc, magnesium and sodium content" and GB/T472.2--1984 "Chemical analysis method of lead ingots - New copper reagent - Medium base orange extraction spectrophotometric determination of silver content".
This standard complies with:
GB/T1.1-1993 Guidelines for Standardization Unit 1: Rules for Drafting and Presenting Standards Part 1: Basic Provisions for Standardization
GB/T1.41988 Guidelines for Standardization Provisions for the Preparation of Chemical Analysis Methods GB/T1467-1978 General Test Rules and General Provisions for Chemical Analysis Methods of Metallurgical Products GB/T7728-1987 General Rules for Flame Atomic Absorption Spectrometry for Chemical Analysis of Metallurgical Products GB/T17433--1998 Basic Terminology for Chemical Analysis of Metallurgical Products Appendix A and Appendix B of this standard are informative appendices. This standard partially replaces GB/T4103.12-1983 and GB/T472.2--1984 from the date of its entry into force. This standard is proposed by the State Bureau of Nonferrous Metals Industry. This standard is under the jurisdiction of the China Nonferrous Metals Industry Standard Metrology and Quality Research Institute. This standard is drafted by Shenyang Smelter and Northwest Copper Processing Plant of Baiyin Nonferrous Metals Company. This standard was drafted by Shenyang Refinery
The main drafters of this standard are Min Jianmei and Zhang Quan. 142
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of lead and lead alloys
Determination of silver content
Methods for chemical analysis of lead and lead alloys-Determination of silver content This standard specifies the method for determination of silver content in lead and lead alloys. GB/T 4103.10-2000
Partially replaces GB3/T4103.12-1983
Replaces GB3/T172.2--1984
This standard is applicable to the determination of silver content in lead and lead alloys. Determination range: 0.00030%~~1.50%. 2 Summary of the method
The sample is dissolved with nitric acid or mixed acid. The absorbance of silver in lead alloy is measured directly by flame atomic absorption spectrometry without separation; silver in lead ingot is separated from the main lead by adsorption with mercapto cotton fiber in acetic acid [c(CHCOOH)=2mol/L] medium, and then the silver is eluted with ammonium thiocyanate solution, and finally the absorbance is measured at 328.1nm wavelength of atomic absorption spectrometer by air-acetylene flame. 3 Reagents
3.1 Nitric acid (pl.42g/mL), high-grade purity. 3.2 Nitric acid (1+3), high-grade purity.
3.3 Hydrochloric acid (1+1), high-grade purity.
3. 4 Zn acid [c(CH,COOH)=2 mol/L] 3.5 Mixed acid: Take 30g tartaric acid and dissolve it in 200mL water, and then add 100mL nitric acid (3.1). 3.6 Ammonium thiocyanate solution [c(NH,SCN)0.5mol/I]. 3.7 Thiourea solution (50 g/L).
3.8 Tartaric acid solution (200 g/L).
3.9 Silver standard stock solution: Weigh 0.5000 g of metallic silver (99.95%), place in a 200 ml beaker, add 50 ml of nitric acid (1+2), heat until completely dissolved. Cool to room temperature, transfer to a 500 ml brown volumetric flask, dilute to scale with water, and mix. This solution contains 1 mg silver per ml.
3.10 Silver standard solution: Transfer 50.00 ml of silver standard stock solution (3.9) to a 500 ml volumetric flask. Dilute to scale with water. Mix. This solution contains 100 μg silver per ml.
3.11 Silver standard solution: Transfer 50.00 ml of silver standard solution (3.10) to a 500 ml volumetric flask, dilute to scale with water, and mix. This solution contains 10ug silver per ml.
4 Instruments and devices
4.1 Atomic absorption spectrometer, with silver hollow cathode lamp. Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Sensitivity: In a solution consistent with the matrix of the measurement solution, the characteristic concentration of silver should not exceed 0.040ug/ml. Approved by the State Administration of Quality and Technical Supervision on 2000-0828, implemented on 20001201
GB/T 4103.10--2000
Precision: Measure the absorbance 10 times with the highest concentration standard solution, and its standard deviation should not exceed 1.50% of the average absorbance: Measure the absorbance 10 times with the lowest concentration standard solution (not the "zero" standard solution), and its standard deviation should not exceed 0.50% of the average absorbance of the highest standard solution
Linearity of working curve: Divide the working curve into 5 sections according to concentration, and the ratio of the absorbance difference of the highest section to the absorbance difference of the lowest section should not be less than 0.85.
See Appendix A (Suggested Appendix) for instrument working conditions. 4.2 Enrichment of base cotton fiber, as shown in Figure 1. 0.1g of sulfhydryl cotton is loaded inside, and water is added to adjust the density of sulfhydryl cotton so that the flow rate is 6-8ml./min. The preparation of sulfhydryl cotton fiber and the determination of sulfhydryl content are shown in Appendix B (suggestive Appendix). $50
Figure 1 Diagram of sulfhydryl cotton red fiber enrichment device
5 Analysis steps
5.1 Test materials
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Silver content, %
0. 000 30~0. 001 0
0. 001 0~0. 002 0
0. 002 0~ 0. 005 0
>0. 005 0-- 0. 008 0
0. 001 0~ 0. 007 0
≥0. 007 0~ 0. 020
2-0. 020~ 0. 10
0. 10-- 0. 50
0.50--1. 00
1.00--1.50
Two independent measurements were carried out and the average value was taken. 5.2 Self-test in air
Self-test with sample
5.3 Determination
Sample quantity·8
Dilution volume, ml.
Volume of test solution, m!
5.3.1 Dissolution and treatment of lead ingot sample
GB/T 4103.10--2000
5.3.1.1 Place the sample (5.1) in a 250ml beaker, add 10~~40ml nitric acid (3.2), cover with a lid, heat at low temperature until the sample is completely dissolved, and evaporate to nearly 400ml. Add 100ml acetic acid, heat and boil until the sample is completely dissolved, and cool to room temperature. 5.3.1.2 Wash the thiourea fiber in the thiourea enrichment device with water 1-2 times, pour the test solution along the wall of the funnel through the thiourea fiber column, wash the beaker and Table III with acetic acid 3-4 times, wash the thiourea fiber 4-6 times, use a liquid-absorbing ball to absorb the residual liquid in the funnel tube and then transfer it to a 50mL volumetric flask.
5.3.1.3 Take 10ml of ammonium thiourea solution, pour it slowly along the wall of the funnel twice, wash the funnel wall and thiourea fiber with water 4-5 times, add 2mL of thiourea solution to the volumetric flask, mix well, add 30mL of hydrochloric acid, dilute to the scale with water, and mix. The following is carried out according to 5.3.3. 5.3.2 Dissolution and treatment of lead alloy sample
5.3.2.1 Place the sample (5.1) in a 250ml beaker, add 20ml mixed acid, cover with Table III, heat at low temperature to dissolve, boil to remove nitrogen oxides, and cool to room temperature.
5.3.2.2 Transfer the test solution to a volumetric flask, dilute to scale according to Table 1, take the test solution into a 100ml volumetric flask, add 2ml thiourea solution, 10ml tartaric acid solution, 5ml nitric acid (3.1), dilute to scale with water, and mix well. 5.3.3 Measurement
Measure the absorbance of the above solution (5.3.1.3 or 5.3.2.2) at a wavelength of 328.1nm on an atomic absorption spectrometer using an air-acetylene flame and zeroing with water. Subtract the absorbance of the blank solution accompanying the sample from the absorbance obtained, and find the corresponding silver concentration from the working curve (5.4.1 or 5.4.2).
5.4 Drawing of working curve
5.4.1 Drawing of working curve for silver in lead ingots Transfer 0.2.50.5.00, 7.50.10.00, 12.50ml of silver standard solution (3.11) into a 250ml beaker and add 100ml of acetic acid. Follow 5.3.1.2 to 5.3.1.3. Under the same conditions as the test sample, measure the absorbance of the standard solution, subtract the absorbance of the "zero" standard solution, and draw a working curve with the silver concentration as the horizontal axis and the absorbance as the vertical axis. 5.4.2 Drawing of the silver working curve in lead alloy Transfer 0, 2.50, 5.00, 10.00, 15.00.20.00.25.00mL of the silver standard solution (3.11) to a 100ml volumetric flask, add 2ml of thiourea solution, 10mL of tartaric acid solution, and 5mL of nitric acid (3.1), dilute to the scale with water, and mix well. Under the same conditions as the test sample, measure the absorbance of the standard solution, subtract the absorbance of the "zero" standard solution, and draw a working curve with silver concentration as the horizontal axis and absorbance as the vertical axis. 6 Expression of analysis results
Calculate the percentage of silver according to formula (1):
Ag(%) - c:VeX 10 × 100
Where:-
Silver concentration found from the working curve, ug/mL; V. Total volume of test solution, mL
V. Volume of aliquoted test solution, mL.
V…--Volume of aliquoted test solution after dilution, mL.; Mass of the sample, g.
The result is expressed to two decimal places. If the silver content is less than 0.10%, it shall be expressed to three decimal places; if it is less than 0.010%, it shall be expressed to one decimal place; if it is less than 0.0010%, it shall be expressed to five decimal places. 7 Allowable difference
The difference between the analysis results between laboratories shall not be greater than the allowable difference listed in Table 2. 145
Silver content
0, 000 30~0. 000 60
0. 000 60-0, 001 5
0. 001 5~0. 003 0
>0. 003 0~0. 005 0
>0.005 0~0.010
>0.010~0.050
>0.050~0.10
0.10-~0.50
≥0. 50 ~ 1. 00
≥>1. 00~~1.50
GB/T 4103. 10---2000
Allowance difference
GB/T4103.10-2000
Appendix A
(Suggestive Appendix)
Instrument working conditions
The operating conditions for determining the amount of silver using WYX-402A atomic absorption spectrometer are shown in Table A1: Table A1
Lamp current
Spectral passband
Burner height
Appendix B
(Suggestive Appendix)
Air flow rate
Preparation of thioglycolic acid fiber and determination of its thiol content
B1 Preparation of thioglycolic acid cotton fiber: Take 20mL of thioglycolic acid (al.32g/ml) and 14 mL of acetic anhydride (ol.08g/mL), put them in a 250mL glass ground-mouth bottle and mix well. Add 2 drops of sulfuric acid (p1.84g/mL), mix well, and cool. Add 4g of absorbent cotton to soak it completely, cover the bottle cap, place it at about 25C for 24h, take it out and squeeze it (wear latex gloves), wash it with water until it is neutral, squeeze it dry, and place it in an oven at 37-38C to dry (about 5h). After cooling, place it in a brown ground-mouth bottle and store it in a desiccator away from light. B2 Determination of the thiol content of base cotton fiber: Take 0.1g of homemade thiol cotton fiber and place it in an enrichment device, and pass 200mL of standard solution (5μg/mLpH6.06.5) through the thiol cotton fiber column. Wash with water 3~~4 times, use a liquid absorption ball to absorb the residual liquid in the column, and connect it to a 25ml volumetric flask. Elute with 10ml. Hydrochloric acid [c(HCI)=1mol/L] solution 10 times, wash with water 4~5 times and dilute to the scale, mix well. Determine the cadmium content by flame source absorption spectrometry. The white content of thiol [SH] in thiol cotton fiber is calculated according to formula (B1): [SH]% = m × 66.14 × 10-3bzxZ.net
m. X 112.4 X 10
Wherein: m,--the measured amount of cadmium adsorbed by thiol cotton fiber, mg; mo---the mass of thiol cotton fiber, g;
66.14--2 times the molecular weight of thiol in base cotton fiber; 112.4·…the atomic weight of cadmium.
The thiol content of thiol cotton fiber shall not be less than 0.40% before it can be used. X 100
(B1)14--2 times the molecular weight of the thiol group of the base cotton fiber; 112.4·… the atomic weight of cadmium.
The thiol content of thiol cotton fiber is not less than 0.40% before it can be used. X 100
(B1)14--2 times the molecular weight of the thiol group of the base cotton fiber; 112.4·… the atomic weight of cadmium.
The thiol content of thiol cotton fiber is not less than 0.40% before it can be used. X 100
(B1)
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